WILMINGTON — Earlier this month, Wilmington and East West Partners – the public and private partners in the downtown River Place project – expressed concern over water springs that have appeared in the construction site between Front and Water streets. The project’s construction manager says the issue is minor, although cost sharing to deal with it has not yet been negotiated.
In early October, McKay Seigel of East West Partners emailed the city, project engineers McKim and Creed, and construction management company MBP Carolinas. Seigel referenced pre-existing springs that had appeared on the site, adding that new springs had been uncovered.
“I believe we got a resolution from McKim and Creed at the time that the water would be fine if left alone, but since have uncovered more springs,” Seigel wrote.
According to Seigel, the city had voiced concern that, if construction was completed on tops of these springs, they could damage Water Street or other surrounding streets.
“The city is concerned that the net result of the springs with the building on top may undermine the road, depending on where the water eventually goes,” she wrote.
From streams to springs
Justin Jacobsen, a senior consultant for MBP, described the issue, which involves groundwater moving downhill towards the riverbed, a process which takes place several feet underground in downtown Wilmington. Construction work at the River Place site has exposed some of these “streams,” which then become “springs.”
Historically, the construction site was the location of the Rock Spring, a source of fresh water for the area for nearly 200 years. In December of 2017, WECT reported that the spring had been unearthed by archeologists working with the city, developer, and contractor of the River Place project.
The newer springs are a bit more active.
“There are currently at least three of these water springs at the site. Two of them are coming out behind the retaining walls at the north and south ends of the excavation, moving down the retaining walls and coming out into the pit at the corners. The third was in a more central area that seems to have been retarded by equipment traffic compacting the surface. Soon it will be covered by a waterproofing membrane and several feet of concrete, at which point the water will likely migrate elsewhere. Once the concrete retaining walls are backfilled, the other two springs will likely do the same,” according to Jacobsen.
Jacobsen said the design team is currently working on a drainage system to make sure the springs return to a subterranean path that doesn’t erode surrounding streets from underneath.
According to Jacobsen, these measures won’t delay the project much, and the cost implications will be “minor,” although the exact cost to the city has not been determined yet.
“The extent of the work is small and the project team worked to solve the potential problem early enough that it can be installed alongside ongoing work, avoiding costly retrofit operations,” Jacobsen said. “Any cost sharing of this item has yet to be negotiated, but the minor additional amount will be handled by existing project contingency funds.”
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